Delayed phosphate release can highly improve energy efficiency of muscle contraction

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Bibliographic Details
Title: Delayed phosphate release can highly improve energy efficiency of muscle contraction
Authors: Jiaxiang Xu, Jiangke Tao, Bin Chen
Source: Biophysical Journal. 124:2303-2316
Publication Status: Preprint
Publisher Information: Elsevier BV, 2025.
Publication Year: 2025
Subject Terms: Biological Physics (physics.bio-ph), Soft Condensed Matter (cond-mat.soft), FOS: Physical sciences, Physics - Biological Physics, Condensed Matter - Soft Condensed Matter
Description: While the power stroke of myosin and the release of inorganic phosphate (Pi) play crucial roles in transforming ATP's chemical energy into mechanical work across diverse biological systems, the exact temporal relationship between these events continues to be intensely debated. In this study, from a functional perspective, we computationally investigate the impact of Pi-release kinetics during the power stroke on muscle contraction dynamics. By implementing a mechanics model of the sarcomere unit that comprehensively incorporates the chemomechanical cycle of individual myosin molecules, we successfully replicate a broad range of experimental observations through parameter variation. Our simulation results reveal that delayed Pi-release can significantly enhance energy efficiency during muscle contraction. This work suggests that a gradual Pi-release that is not directly coupled with the lever arm swing may offer a route to adjust the stability of a working myosin on the actin filament, thereby modulating the power stroke to influence muscle contraction.
Document Type: Article
Language: English
ISSN: 0006-3495
DOI: 10.1016/j.bpj.2025.06.002
DOI: 10.48550/arxiv.2406.09670
Access URL: http://arxiv.org/abs/2406.09670
Rights: Elsevier TDM
arXiv Non-Exclusive Distribution
Accession Number: edsair.doi.dedup.....352450c78d063692a8aee3da4a125bad
Database: OpenAIRE
Description
Abstract:While the power stroke of myosin and the release of inorganic phosphate (Pi) play crucial roles in transforming ATP's chemical energy into mechanical work across diverse biological systems, the exact temporal relationship between these events continues to be intensely debated. In this study, from a functional perspective, we computationally investigate the impact of Pi-release kinetics during the power stroke on muscle contraction dynamics. By implementing a mechanics model of the sarcomere unit that comprehensively incorporates the chemomechanical cycle of individual myosin molecules, we successfully replicate a broad range of experimental observations through parameter variation. Our simulation results reveal that delayed Pi-release can significantly enhance energy efficiency during muscle contraction. This work suggests that a gradual Pi-release that is not directly coupled with the lever arm swing may offer a route to adjust the stability of a working myosin on the actin filament, thereby modulating the power stroke to influence muscle contraction.
ISSN:00063495
DOI:10.1016/j.bpj.2025.06.002